Control device



1943- A. N. AYERS CONTROL; DEVICE Filed April 15, 1941 Inventor; Alan N Ayer s, by 6: x]

- His Attorney of the container is filled with an Patented Aug. 17, 1943 CONTROL DEVICE Alan N. Ayers, Devon, Conn,

Electric Company,

assignor to General a corporation of New York Application April 15, 1941, Serial No. 388,637

9 Claims.

My invention relates to temperature or pressure responsive control devices, more particularly to control devices for electrically driven refrigerators, and has for its object a simple, inexpensive and reliable control device of this character.

In carrying outmy invention in one form, I provide a sealed fluid container having a portion containing an expansible fluid which is exposed to the temperature to be controlled, such as the evaporator of a refrigerator or the airtemperature in a refrigerator compartment. Another portion of the container contains an electrically conducting liquid, preferably mercury, the static head of which varies in accordance with the pressure of the expansible fluid and cooperates with electrical contacts to control the starting and stopping of the refrigerating apparatus. This fluid container has the whole or portion of it mounted for adjustment about two substantially horizontal axes at right angles with each other whereby the static head of the mercur can be varied to adjust the range of temperature variation in the refrigerator required to start and stop the refrigerating apparatus, and also to adjust the average temperature maintained in the re- Irigerator.

For a more complete understanding of my invention, reference should be had to the accompanying drawing, Fig. 1 of which is a side elevation view of a control device embodying my invention; Fig. 2 is an end elevation view of the device shown in Fig. 1; while Fig. 3 is a diagrammatic view showing a typical refrigerator provided with a control device tion.

Referring to the drawing, in one form of my invention I provide a sealed tubular container ll provided with a U-shaped" portion Illa at one end containing a predetermined quantity of mercury II. This U-shaped portion Illa, as seen in the drawing, extends downward and laterally crosswise, as shown in Fig. 2, with respect to the remainder of the container which includes a substantially straight portion 12. The remainder expansible fluid whose volume varies with its temperature such as a gas. Preferably, this container normally is held in substantially the position indicated in Figs. 1 and 2 with the straight portion l2 substantially horizontal and the U-shaped portion "a in a substantially vertical plane at right angles with the center line of the tubular portion l2 and with its arms extending upward from a bottom portion connecting said arms. The quantity of mercury ln'the U-shaped portion should preferably be somewhat more than required to fill the lefthand arm of the U-shaped portion as seen in Fig.2, 1. e., the arm terminating in the end 01 the tubular container.

It will be understood that the expansible gas embodying my invenin the container is maintained under'a pressure determined by and proportional to the temperature of the gas. This gas pressure is applied to the surface of the mercury in contact with the gas in the U-shaped portion of the container and forces the mercury downward in the right-hand arm, as seen in Fig. 2, until the gas pressure is balanced by the static head of mercury represented by the difference in the levels ofthe mercury in the two arms. In a device suitable for the control of a refrigerator, such as shown in the drawing, the gas pressure at normal room ambient temperatures will be great enough to force the mercury upward nearly to the end of the left-hand arm which is evacuated of air and other gases as indicated in the drawing or completely to fill the left-hand arm.

As seen in Fig. 1, the extreme left-hand arm of the U-shaped portion of Fig. 2 is provided with a portion 10b extending at a slight angle upward with the horizontal. In this portion Illb are two electric contacts l3 and I4 extending into the interior of the container so as to be covered and electrically connected together by the mercury as shown in the drawing. These contacts are in the circuit of an electric motor l5 which is connected to drive a suitable refrigerator compressor [6, energy being supplied from suitable supply mains ll.

The container [0 is suitably supported for angular adjustment about two horizontal axes which are at right angles with each other for the purpose of varying the static head of the mercury ll. As shown, the tubular portion I2 is journaled for limited angular rotation about its longitudinal axis in a supporting member [8, the portion of the tube I! in the support i8 being normally substantially horizontal. Also, the member I8 is mounted for angular adjustment about a pivot pin I9 which is shown as a bolt with the wing nut 2|! for securing the member It in a desired angular position on the bolt Hi. This adjustment of course varies the angular position of the portion of the tube I: in the support It.

Thus angular adjustment of the container about the axis of the tube l2, which may be made by turning a knob 2| secured to the container, varies the static head of mercury applied to the expansible gas and thereby adjusts the temperature required to cause the gas to force the mercury upward and electrically connect together the two contacts l3 and I4.

Also, adjustment of the container about the axis l9 varies the relative heights of the two contacts I3 and I4 and therefore varies the static head of mercury between the two contacts and, consequently, the change in pressure in the gas and change in temperature, 1. e., temperature range or gradient, required to produce this pressure to cause the mercury electrically to connect together the two contacts.

The tubular portion I2 is extended to the point whose temperature is to control the refrigerator. The tube may simply extend into a selected part of the refrigerator cooling chamber so as to be responsive to the air temperature of the chamber at that point. Preferably, however, it is brought at its end into good heat conducting or thermal relation with the evaporator of the refrigerator. In order to maintain this thermal relation, while at the same time providing for the necessary limited angular adjustmentspreviously described, a flexible, braided copper strap 22 is provided having one end secured to the tube I2 and its other end secured to the evaporator of the refrigerator in good thermal relation therewith. Thus the strap 22 provides for a free exchange of heat between the end of the tube and th evaporator so that the tube is maintained at the temperature of the evaporator while it is flexible enough to provide for adjustment of the container.

In Fig. 3 the device of Figs. 1 and 2 is shown mounted on the evaporator 23 in the food compartment or box 24. The knob 2I is conveniently accessible for adjustment of the temperature to be maintained, while the heat conducting strap 22 is secured to the side of the evaporator. The wing nut 20 providing for adjustment about the bolt'IB need not be so conveniently accessible because ordinarily this. adjustment for temperature range will be made in the factory when the apparatus is assembled.

As shown in Fig. 3, the motor I5 and the compressor I6 driven by it are enclosed in a sealed casing 25. The compressor supplies liquid refri erant to the evaporator or cooling element 23 through a suitable condenser 26 and a float cham ber 21, these parts being connected through a conduit 28. The gaseous refrigerant is withdrawn from the evaporator 23 through a conduit 29 to the compressor.

Preferably, as shown, the tubular portion I2 is the highest part of the container I0 so that the mercury can not collect in the tubular portion. The U-shaped portion Illa may, for example, be made of glass with the terminals I3 and I4 extending through the glass into position to be engaged by the mercury when the mercury head is high enough.

While I have shown a particular embodiment of my invention, it will be understood, of course, that I do not wish to be limited thereto, since many modifications may be made and I, therefore, contemplate by the appended claims to cover any such modifications as fall within the true spirit and scope of my invention.

What I claim as new and desire to secure by Letters Patent of the United States, is:

1. A control device comprising a closed container provided with a lower portion and a higher portion, said portions being interconnected in said container, an upright leg at the end of said lower portion, a quantity of mercury in said lower portion, an expansible fluid in said higher portion, spaced apart electric contacts in said upright leg arranged to b electrically connected together by said mercury when said mercury is forced by said expansible fluid to a predetermined height in said upright leg, and means for supporting said container for pivotal movement about a substantially Lorizontal axis to vary the height of said contacts relative to each other and for pivotal movement about an axis substantially at right angles to said first axis to vary the static head of said mercury applied to said expansible fluid.

2. A control device comprising a closed elongated container provided with a substantially straight portion and a laterally extending U-shaped portion at one end having one arm connected to said straight portion, means for supporting said container with said straight portion substantially horizontal and the arms of said U-shaped portion extending upward from a bottom portion connecting said arms together, a quantity of liquid electrically conducting material in said U-shaped portion, an expansible fluid in the remaining portion of said one arm and in said straight portion, and an electric contact in the other outer arm of said U-shaped portion arranged to be engaged by said material when said material is forced by said expansible fluid to a predetermined height in said outer arm, said supporting means providing said container for limited angular movement of said container about said straight portion to vary the static head of said material required .to connect together said contacts.

3. A temperature control device comprising a closed tubular container provided with a substantially straight portion and a laterally extending U-shaped portion at one end having one arm connected to said straight portion, means for supporting said container with said straight portion substantially horizontal and said U-shaped portion with its arms extending upward from a bottom portion connecting said arms together, a quantity of mercury in said U-shaped portion of said container, a fluid whose volume varies with its temperature in the remaining portion of said one arm and in said straight portion, and electric contacts in the end of the other outer arm of said U-shaped portion arranged to be connected electrically together by said mercury when saidmercury is forced by the pressure of said fluid to a predetermined height in said outer arm, said supporting means providing said container for limited angular movement of said U-shaped portion about said straight portion to vary the static head of said mercury required to connect together said contacts and thereby vary the temperature of said fluid required to connect together said contacts.

4. A temperature control device comprising a sealed U-shaped container made of electrically insulating material, means pivotally supporting said container for angular movement about an axis which is substantially horizontal and parallel with the plane of said U-shaped container,

said container being held by said supporting means normally with its plane in an upright position, and its arms extending upward from a bottom portion connecting said arms together, an electrically conducting liquid partly filling said container, a fluid whose volume varies with its temperature .in one arm of said container, electric contacts in the end of the second arm of said container spaced apart'in a direction at right angles to said axis and arranged to be connected electrically together by said liquid when said liquid is forced by the pressure of said fluid to a predetermined height in said second arm, said container being adjustable about said axis to vary the heights of said contacts relative to each other.

5. A temperature control device comprising a sealed U-shaped container made of electrically insulating material, means pivotally supporting said container for angular movement about a first axis substantially at right angles with the plane of said U-shaped container, said container being held by said supporting means normally with its Diane in an upright position and its arms extending upward from a bottom portion connecting said arms together, an electrically conducting liquid partly filling said container, and a fluid whose volume varies with its temperature in one arm of said container, spaced electric contacts in the end of the second arm of said con tainer arranged to be connected electrically together by said liquid when said liquid is forced by the pressure of said fluid to a predetermined height in said second arm, said container being adjustable about said first axis to vary the static head of said liquid required to connect together electrically said contacts thereby to vary the temperature of said fluid required, to connect together said contacts.

6. A temperature control device comprising a sealed U-shaped container made of electrically insulating material, means pivotally supporting said container for angular movement about a first axis substantially at right angles with the plane of said U-shaped container, a second supporting means for pivotally supporting said container for angular movement about a second axis which is substantially horizontal and at right angles with said first axis, said container being held by said supporting means normally with its plane in an upright position and its arms extending upward from a bottom portion connecting said arms together, an electrically ,conducting liquid partly filling said container, and a fluid whose volume varies with its temperature in one arm of said container, horizontally spaced electric contacts in the end or the second arm of said container arranged to be connected electrically together by said liquid when said liquid is forced by the pressure or said fluid to a predetermined height in said second arm, said container I being adjustable about said first axis to vary the static head of said liquid required to connect together electrically said contacts thereby to vary the temperature of said fluid required to connect together said contacts, and adjustable about said second axis to vary the heights of said contacts relative to each other.

7. A temperature control device comprising a closed tubular container made of electrically insulating material provided with two substantially parallel straight portions and with a U-shaped portion extending substantially at right angles with said parallel portions and connecting said parallel portions to each other, supporting means for said container cooperating with a first of said straight portions so as to provide for limited first turning adjustment of said first substantially straight portion about its longitudinal axis,

when said mercury is forced by the pressure of said fluid in respons to a change in temperature to a predetermined height in the second arm oi said U-shaped portion, said container being adjustable about said first axis to vary the static head of said mercury required to connect together said cont ts and thereby vary the temperature of sai fluid required to connect together said contacts and said container being adjustable about said second horizontal axis to vary the height of said contacts with relation to each other thereby to adjust the change in temperature required to cause said mercury to connect and disconnect electrically said contacts with relation to each other.

8. A control device comprising a closed tubular container made of electrically insulating material provided with a substantially straight portion and with a second portion on one end of said straight portion having two arms extending substantially at right angles with said straight portion, supporting means for said container cooperating with said straight portion so as to provide tor a limited turning adjustment of said straight portion substantially about its longitudinal axis, said container being normally supported in such position that said straight portion is substantially horizontal and said second portion extends below said straight portion with said arms extending upward from a bottom connecting portion, a quantity of mercury in said second portion, a fluid whose volume varies with its temperature in said straight portion and in a first connecting arm of said second portion, an electric contact in the other arm of said second portion engaged by said mercury when said mercury is forced by the pressure of said fluid in response ot a change ini temperature to a predetermined height in said second arm, and means for thermally connecting said straight portion to a temperature variable body, said thermal connecting means providing for limited turning adjustment of said container about said straight portion while maintaining said thermal connection.

5 9. A control device comprising a closed tubular container made of electrically insulating material provided with a substantially straight portion and with a U-shaped portion on one end of said straight portion having its arms extending substantially at right angles with said straight portion, supporting means for said container cooperating with said straight portion so as to provide for a limited turning adjustment of said straight said supporting means being in turn mounted for a second turning adjustment about asubstantially horizontal axis substantially at right angles with said first straight portion, said container being normally adjusted about said axes so that said straight portions are substantially horizontal and said U-shaped portion extends downward from said straight portions, a quantity of mercury in said U-shaped portion filling the'lower end of said U-shaped portion, a fluid whose volume varies with its temperature in said first straight portion and in a. first connecting arm of said U-shaped portion, a pair of electric contacts in said second straight portion, saidcontacts being spaced apart along the length or said second straight portion and being normally maintained at diflerent heights whereby said contacts are electrically connected to ether by said mercury portion substantially about its longitudinal axis, said container being normally supported in such position that said straight portion i substantially horizontal and said U-shaped portion extends downward from said straight portion with the arms of said U-shaped portion extending upward from its bottom connecting portion, a quantity of mercury in said U-shaped portion filling the lower end of said U-shaped portion, a fluid whose volume varies with its temperature in said straight portion and in a first connecting arm 0! said U-shaped portion, an electric contact in the second arm of said U-shaped portion engaged by said mercury when said mercury is forced by the pressure of said fluid in response to a change in temperature to a. predetermined height in said second arm, and means for thermally connecting said straight portion to a temperature variable body providing for limited turning adjustment at said container about said straight portion while maintaining said thermal connection.

ALAN N. AYERS. 

